Pumping mechanisms



Aug.I 6, 1957 G. w. I Ewls PUMPING MECHANISMS Filed June 8, 1955 United States Patent() PUMPIN G MECHANISMS George W. Lewis, Toledo, Ohio Application June 8, 1955, Serial No. 513,965

3 Claims. (Cl. 10S-150) This invention relates to pumping mechanisms adapted to be used in fuel transfer as well as vacuum supply systems for self-propelled vehicles, more particularly to pumping mechanisms of the reciprocable type operated by driving means having a constant stroke while the pumping element may have strokes of variable magnitude.

The invention comprehends a pump in which the shock of engagement due to relative movement of the pumping element with respect to its driving mechanism is reduced to a minimum by providing automatic take-up means for damping the various inertia or suddenly applied forces which are encountered both in starting the pumping element from rest or after back pressure in the pumping chamber has been released.

The invention comprises a mechanism whereby a driving connection is established between a continually operated part `having a uniform throw and a pumping element through its handling member permitting a change in the operative range or the length of the stroke of the pumping element without the interruption of the driving connection. The invention contemplates an arrangement whereby a rolling metallic contact is provided for the actuating mechanism `of a pumping element, providing elastic means to keep the actuating mechanism in constant engagement with the power driving part as well as the pumping element, and wherein the reaction forces on the actuating mechanism fulcrum pin are in one direction thereby eliminating possible noise at the various points of engagement.

The invention embraces power transmitting composite lever means having a yielding acting component in alignment therewith to provide a rolling metallic contact ltherebetween, which rolling contact is obtained in practice by forming to a curved section either the lever proper or the yielding acting component, so that there is separation therebetween, which separation, and thereby the yielding of the composite lever means, is gradually decreased upon the transmission of power.

According to the foregoing summary of the invention indicating its nature and substance, one of the main purposes is the provision of a novel force and motiontransmitting mechanism wherein a constant communication is established between the power-driving member andthe pumping element which mechanism automatical- 1y takes` up looseness of the components and relative motion caused by pressure in the pumping chamber, as well as suppressing wohbling, uncontrolled movements and objectionable vibration, to secure thereby a pump y,of high eciency in operation, very quiet in action. and -having long ,life under service conditions in self-propelled vehicles. f i In conventional pumping devices, particularly diaphragm pumps in present use, a lost motion connection is provided between the operating lever actuated by an engine-driven part having a uniform throw and the resirraablervmpins element .0r diaphragm in arder .t9

ice

permit a change in the stroke of the pumping element when pressure is built up within the pumping chamber."

The presence of the lost motion connection results in undue stresses and objectionable noises on account of the shock of engagement of the components; in addition, the use of such connection permits wobbling, uncontrolled movements and objectionable vibrations of the diaphragm which contribute to loss of pumping eciency and cause performance failures after `a comparatively short time in use.

It is one of the objects of the invention to overcome the objectionable features and suppress the contributing factors for the performance failures of conventional pumping devices by providing an actuating assembly which may be termed an elastic coupling interposed between the power-driving part and the pumping element, the composite assembly not only transmitting force and motion but also functioning in a four-fold manner (l) as means to take up any shock caused by the engagement of the lever means with the handling member of a pumping element, insuring thereby quiet operation by suppressing uncontrolled movements and undesirable vibrations, particularly in the critical speed range, (2) as means to effectively guide the handling member and thereby the pumping element during its operative range, (3) as means to provide a uni-directional force for keeping under tension the pumping element and applying a force in only one direction on the fulcruming means, and (4) as means to to constantly urge one component of the assembly into engagement with the continually power-driving part. i i

One object of the invention is to provide a motion and force-transmitting mechanism constantly connecting the power-driving member and a pumping element but permitting changes in the amplitude of the motion transmitted by the use of spaced members in alignment, one yielding into engagement with the other, whereby the rigidity of the mechanism constantly increases as the separation between the members decreases, f

Another object of the invention is to provide a lever mechanism in which a rigid` lever arm is provided with a divergent yielding acting member attached thereto for engagement therewith upon the transmission of force to a `pumping element, and said rigid arm and member being curved with respect to the other so that their contacting engagement is in an asymptotic line relationship whereby the rigidity of the lever mechanism increases as the force transmitted to the pumping element increases.

Another object of the invention is the provision in a pump of a power-transmitting mechanism having a section formed by rigid primary and yielding secondary aligned arms having forked ends which straddle the handling member of the pumping element for guiding and applying a constant predetermined tensioning force, said arms being constructed and arranged so that a yielding action of the secondary arm decreases when said arms are urged into engagement whereby the rigidity of the :section increases upon the transmission of power.

A further object of the invention is to provide a powertransmitting mechanism including a rigid lever arm with a yielding acting cantilever arm attached thereto arranged in spaced alignment therewith being adapted to be placed into contact with the rigid arm upon the transmission of force and one of said arms being curved with respect to the other whereby the point of contact established therebetween may be varied as a function of the force being transmitted. l 1

A` further object of the invention is the improvement of arpump of the type disclosed in U. S. Patent No. 2,625,113 of January 13, l953 to K. I. Robinson et al.

Other objects and advantages of this invention relatins t0 the arrangement, Operation and, function @filierelated elements of the structure, to various details of construction, to combinations of parts and to economies of manufacture, will be apparent to those skilled in the art upon consideration of the following description and appendedclaim's, reference being had to the accompanying drawings forming a part of. this specification wherein like referencecharacters designate corresponding parts in the several views.

Fig. I is a median vertical sectional View of a pump illustrating the invention;

Fig. II is a side view ofthe motion and force-transmitting mechanism showing the relationship of the parts under no load condition; l

VFigIII is a top plan view of the mechanism shown in Fig. II;1H

Fig. IV is a median vertical sectional view of a pump illustrating a modified form of the invention;l

Fig. V is a cross-sectional view of the force and motion-transmitting mechanism illustrated in Fig. IV sho. ing the relationship of its components under no load condition;

l Fig. VI is a bottom plan view of the mechanism shown in Fig. V. c

Although the present invention is herein described with particular reference to a diaphragm pump similar to the one disclosed in U. S. Patent No. 2,625,113, it should be clearly understood that the principles of the invention are believed to be applicable to other types of reciprocable pumps in which provision is made for a change in the pumping stroke when pressure is built upv within the pumping chamber. It should be further understood that the invention should not be limited to the particular forms shown and that it is contemplated to use the same whenever the invention may be found to be of utility.

Referring to the drawings, and particularly to Fig. I, in which the pumping mechanism of the invention is illustrated, it can be seen that the main support or housing is formed of two hollow members or complementary sections and 12 provided with uniplanar mating flanges 13 and 14 formed at the periphery of their corresponding recessed' portions. The housing sections 1li and 12 are joined together by suitable fastening means such' as threaded members 15 clamping therebetween the pump'- ing element which is shown in the form of a flexible diaphragm 16 spanning their recessed' portions providing a movable wall therefor and, by its cooperative relationship, producing opposed closed chambers 17 and 18. The lower closed chamber 17, which is beneath the diaphragm 16, constitutes the pumping chamber, while the upper closed chamber 13, defined by the upper surface of the diaphragm and the recessed portion of member 12, forms a distendable compartment suitably vented to the atmosphere by opening I9.

Suitable inlet and outlet valves are provided in the respective passages leading to and from the pumping chamber 117 which are of a construction similar to the one illustrated in the patent herebefore mentioned. The diaphragm 16 is provided with a handling member or its equivalent which is directly connected or attached to its central portion in leak-proof relation. In the form shown, the handling member is illustrated as a headed pull rod`v or slidable stem 20 formed at its lower end-with al steppedl portion providing a shoulder 21, from which projects a reduced end section 23. The end' section 23 snugly projects through aligned openings provided in the opp'ositely disposed, shallow cupped discs or reenforcing plates 24 and 25, as well as in the diaphragm 16 and, by spinning the end of the reduced section 23, as at 26, clamps the diaphragm between the reenforcing plates, providing therebyl a duid-tight connection.

The transverse wall 27, which actsas a partition of the housing section 1-2 for-ming the open compartment 28, and the top section of tlie closed" chamber 18 isfpierced by flanged-aperture 29, through which extendsthe en- Ia'rge'dlhead 30 of the handling member 20. The compartment 28'i'sprovided at its open end with peripheral flange 31, by means of which the pump is adaptedto be detachably connected to -the crankcase of the engine or other prime mover supplying the power for operating the mechanism which reciprocates the diaphragm.

In order to prevent the ingress of oil or foreign matter into the distendable chamber 13 from the open compartment 28 by the aperture 29, the reciprocable member 20 is provided with a flexible sealing member having a central nipple 32 which sealingly fits the shank of the handling member 20 projecting through the aperture 29 slightly above the surface of the transverse wall 27. The nipple of the sealing member terminates into a horizontally disposed peripheral ange 34 arranged to overlie the lip of the llanged aperture 29 and is resiliently urged thereagainst through the metal retainer 35 by helical spring 36 compressed between the diaphragm reenforcing plate 25 and the horizontally disposed flange 33 of the retainer 35. This sealing arrangementy eiTe'c-ti-vely prevents oil seepageand the ingress of foreign matter into the chamber 18 without interfering with the freedom of movement of the handling member 20. l

The compartment 18 is 'arranged to house the resilient means for conditionally effectingV the motion of the pumping element or diaphragm in one direction. In the form shown, the compartment 18' is designed to enclose and retain under a predetermined force the resilient member in the form of a compressible helical spring 37 which serves as resilient means for conditionally urging the diaphragm downwardly to collapse the pumping chamber 17 to eiect the expulsion or discharge stroke of the pump. The spring 37 is held in position, avoiding any possibility of interference with the movement of the handling member 20 and with the seal retainer spring 36 by means of the concentric corrugations providedV on the reenforcing plate 25 for engagement with the bottom end of the spring and by the inner surface of theV lateral wall defining the top of the compartment 18 for the' top end of the spring 37.

In the form of the inventionV shown in Fig. I, a cam 3S rotated by a shaft 39 which may be, for'eXarnpl, a crankshaft or camshaft or the like of a prime mover, is intended as a representative of a continually reciprocating' or rotating part having a suitable uniform throw which' constitutes the power driving part used to impart movement to the handling member 2l) for actuating the pumping element.

One of the important features of the invention deals particularly' with a motion and torque-transmitting mecha'- nism interposed as an elasticY coupling between the power driving part, such as the cam 3S, and the handling mentber 20 attached to the'recip'rocable but pressure-responsive pumping element. The power-transmitting mechanism', providing automatic take-up and noise-suppressing'means', according to the preferred form of the invention, is" inclusive of lever means fulcrumed or pivotedV on a stationary part, such as the casing'12'. The lever means extends -on eac-h side of its pivotal axis forming a rigid outer arm adapted to engage and be operated by the power driving cam 38 and a composite inner arm structure which in'- cludes a rigid section and a yielding acting' part spaced from and aligned for engagement therewith, which partis in constant engagement with the' handling member, whereby the lever means forms a constant connection forl tlie transmission of motion and force which is substantially rigid under certain conditions 4of operation andJ provides a decrease in rigidity under other operating conditions.

In the embodiment of the invention shown in' Figs'. I to III inclusive, the power-transmitting mechanism' comprises a lever 40 pivoted at itsmedian section on Suitable means, such as by the pin 41, carried by the lateral walls of the casing section 12. The lever 40 is shown as formed with a uniplanar top surface extending at each sid'e of:y its pivotal axis 41 which forms a rigid outer arm 42' adapted to contact the continually operating' part orl cam 3'8- and a composite inner arm structure, including the rigid section 43, which isl a continuation of the lever proper' and'y a yieldingl acting part 45, which-may take? the form` ofa" thin plate inherently elastic fixed to the top surface of the outer arm 42 at a point located rearwardly of its pivotal axis.

The yielding acting part 45 of the lever 40, as particularly illustrated in Fig. II, is shown inthe form of a leaf spring having one of its ends riveted as at 46 to the top surface of the lever at a point rearwardly of its pivot and is arranged to be biased toward an angular relationship to the longitudinal axis of the` lever or divergent to its uniplanar top surface. The leaf spring 45 is properly biased to serve as an elastic linger of the lever 40 constantly engaging the enlarged head 30 yof the pull rod or handling member even at times when a pressure built up within the pumping chamber 17 serves to holdthe handling member in its uppermost position so as to render the rotation of the cam 38 temporarily ineffective to irnpart further reciprocatory movement to the diaphragm. In order to secure the proper biased relationship and preferably produce mutual contacting engagement in an asymptotic line between the members 45 and 43, the leaf spring 45 is formed with a ilat end section 47 and the remainder of the body portion is curved whereby not only the angular relationship is accomplished but a rolling contacting engagement is provided between the leaf spring 45 and the uniplanar top surface of the lever 40. cam 38 and a composite inner arm structure which in- `As particularly shown in Figs. II and Ill, the inner arm 'of the lever 40 is in the form of a composite bifurcated structure which includes divergent arms 43 and 45 of substantially the same length and in vertical alignment, wherein the arm 43 is formed with a forked end section 49 and the yielding acting arm 45 is also formed with a forked end section 50. Both of the forked end sections 49 and 50 `are adapted to straddle the shank orthe handling member 20, as particularly shown in Fig. I. The yielding acting arm or leaf spring 45 is arranged so that its forked end 50 is in constant engagement with the bottom surface of the enlarged head 30 of the handling member snugly straddling its shank and with the end of the forked section abruptly bent, as at 51, so that the furcations are also in engagement with the side walls of the head 30 of the handling member, thereby providing a constant pull on the diaphragm and also constantly guiding the handling `member 20 during the operation of the pumping mechamsm.

In the form of the invention shown in Figs. I to III inclusive the rigid component of the actuating assembly, which is shown as a pivoted lever 40, may be of any suitable non-yielding material. However, it is contemplated, for sake of lightness and in order to attain the optimum strength/weight ratio, to use a sheet metal member having a channel or U-shaped configuration. The lever is preferably fabricated from a sheet steel blank bent or shaped into a channel having back and side walls substantially at right angles with the back or web of substantially uniform width throughout its length. The side walls are substantially parallel while their median sections .52 are ofset or struck out forming an enlarged portion with aligned apertures 53 to accommodate the pivot pin 41 and the remainder gradually decreasing in height or tapering from their median sections 52 toward their respective extremities.

The operation of the form of the invention hereinbefore `describedwis such that whenever the cam 38 is rotated, a rocking motion is imparted to the pivoted arm 40 whereby its rigid inner portion 43 is moved or cycled clockwise and counter-clockwise to effect the reciprocatory movement of the diaphragm 16 through the yielding acting member 45 constantly connected to the handling member 20. Assuming the parts are in the position shown in Fig. I, and that the rigid portion 43 of the lever 40 is moved counterl. clockwise by rotation of the cam 38, motion will be imparted through the yielding acting member 45 to lift or eX there is no back pressure in the pumping chamber 17, the rigid arm 43 of the lever will be in contact throughout its full length with the leaf spring or yielding acting member 45 on account of the opposition offered to such movement by the springs 36 and 37. Thus, the inner bifurcated sections 43-45 of the lever 40 is substantially unyielding, so that its working stroke corresponds to the full travel of arm 43 whereby the diaphragm 16 will be positively moved upwardly compressing the springs 36 and` 37 storing energy therein during the full length of its travel in a counterclockwise direction.

Further rotation of the cam 38 will change the movement of the bifurcated section 43-45 from counterclock to clockwise direction whereby the energy stored in the springs 36 and 37 during its movement in a counter-clockwise direction will be released to push the diaphragm 16 downwardly as the bifurcated section is moving in the same direction. The downward movement of the diaphragm 16, conditionally produced by the resilient members 36 and 37, decreases the volume of the pumping chamber 17, bringing about the discharge or expulsion stroke of the pump. This mode of operation wherein the Working stroke of the lever is equal to substantially the full length of its travel in a counter-clockwise direction will continue as long as pressure is not present within the pumping chamber.

As `before pointed out, the presence of pressure within the pumping chamber 17 pushes up the diaphragm compressing the springs 36 and 37 moving upwardly its handling member 20 with the aid of the constantly pulling leaf spring 45 relative to the rigid section 43 of the lever 40. This relative movement decreases the length of engagement changing the spacing or longitudinal angular relationship of the leaf Spring 45 with respect to the rigid arm 43 of the lever whereby the rigid member 43 has a sliding non-Working motion with respect to the handling member 20. The extent of such non-working motion is dependent upon the position to which the diaphragm is pushed up in response to the amount of built-up pressure Within the pumping chamber. It should be noted that the length of the working stroke of the lever decreases as the length of the contacting engagement of leaf spring 45 with the rigid arm 43 decreases in the same ratio, and that the length of their engagement is dependent upon the amount of pressure built up Within the pumping chamber and is a function thereof. Notwithstanding the fact that the rigid arm 43 has a non-working motion when pressure occurs within the pumping chamber, this invention obviates contact noise and provides a slappreventing means as the load imposed on the lever means in further compressing the springs 36 and 37 is gradually taken up by increasing the length of engagement of the arm 43 with the leaf spring 45.

The increase in the length of the contacting engagement of the rigid lever section 43 with the cantilever spring 45 occurs gradually as the load imposedl by the resilient members 36 and 37 is taken up by the actuating lever because this increase is the result of forcing together into rolling point `contact the spring and lever section from a divergent position into a full length engagement condition to produce a substantially rigid lever arm for positively transmitting the additional force to further move the diaphragm 16. Thus, the resiliency, and therefore the length of the cantilever of the spring 45, decreases as the force transmitted increases to effect the transmission of force in a substantially rigid condition as it is con templated that the rigid portion 43 of the lever is slightly longer than the effective length of the spring 45 when full length engagement takes place. t

In the form of the invention shown in Figs. IV to VI inclusive, in which only the lower portion of a composite housing of a pumping mechanism is illustrated, the

flexible diaphragm 56, liXed at its periphery, constitutes the movable wall of the pumping chamber 57 located thereabove and defines, with the recessed portions of the housingmember 62 located therebeneath, adistendablp l 7 compartment 58 suitably vented to the atmosphere. The vflexible diaphragm 56 carries, at its central portion, a

vhandling member or pull rod 60, which is formed at its other extremity with a stepped section providing a shoulder 61 and a reduced end section 63. The reduced end section 63 of the pull rod 60 projects through the diaph'ragm and the oppositely disposed reinforcing plates 64 and 65 and has the same riveted as at 66 forming a uid-tight connection between the diaphragm and the pull rod.

The housing 62 is formed with a horizontally disposed wall 67 which acts as a partition forming the open-ended chamber 68 and the bottom wall of the distendable compartment 58 is formed with an aperture 69, through which extends the enlarged head 7@ of the pull rod 60. The Vchamber 68 is provided at its open end with a peripheral flange 7l, by means of which the pumping mechanism may be secured to an internal combustion engine, or other power supply means, for actuating the mechanism which reciprocates the diaphragm.

The pull rod 6d is provided with a sealing boot, preferably a rubber-like material, having a central tubular section 72 which snugly fits the shank of the pull rod and `from which depends a flared conical section terminating into a horizontally disposed flange 74 arranged to span the aperture 69. The flange 7d is urged into tight engagement with the top surface of the wallA 67 through rthe retainer 1'5 by the helical spring 76 held under compression in the distendable compartment S8. This sealing arrangement prevents the ingress of oil or other foreign matter from the open-ended chamber 68 into the dis'ten'dable compartment 5S without interfering in any way with the freedom of movement of the handling member 60. The helical spring 76 in the modified form of the invention performs the double function of holding the sealing boot in position as well as conditionally producing the `discharge stroke of the pump and is held in concentric relation with respect to the pull rod by having one end surrounded by corrugations 77 provided in the reinforcing plate 65 and its other end snugly fitting the upstanding section of the retainer 75. fn this embodiment of the invention, the continually operated cam 73 rotated by shaft 79 constitutes the power driving part having a uniform throw used to impart movement to the handling member 60 for reciprocating the diaphragm 56.

The power-transmitting mechanism, acting as an elastic coupling which functions as automatic take-up means for damping the various inertia and uncontrolled vibratory motions of the ydiaphragm in'this form of the invention,

is inclusive of an actuating lever till pivoted adjacent one of its ends ona pin 8l journaled on the lateral walls of .the open-ended chamber 68 of the housing section 62.

The actuating lever 80, preferably made of sheet steel of channel-shaped cross section, comprises an outer arm 82 having a uniplanar longitudinal surface located rearwardly of its pivotal axis for contacting engagement with the continually-operated cam 78 and an inner composite bifurcated section. This section is formed by the rigidv curved section 53 which is continuation of the lever proper and a yielding acting part which is shown as a flat spring 35, one end of which is fixed to the arm 82 rearwardly its pivotal axis.

As particularly shown `in Fig. V, the leaf spring 85 has one of its ends riveted as at 36 to the bottom surface of the actuating lever and in its non-operative position formsv a continuation of the uniplanar section 82 of the lever. ln this form of the invention the rigid inner section 83 is curved and arranged to provide a predetermined angular relationship with the longitudinal axis of the lever, so that the leaf spring 85 is inherently biased to serve as an elastic finger of the actuating lever 80. As a result of this angular relationship, the spring S isAV in constant engagement with the enlarged head 70 of the pull redet), even at times when pressure is present within the pumping chamber' 57 which pushes the diaphragmlplacing-theV pull rod-60 in the position shown in Fig. IV so as to render rotation of the cam 7 S temporarily ineffective to impart full reciprocatory movement to the diaphragm. The curvature of the inner section 83 of the lever provides a suitable configuration whereby a rolling point contact occurs when the leaf spring S5 is forced into full engagement with the curved section 33, producing a substantially rigid unit for the transmission of force to pull the diaphragm 56".

In the modified form of the invention, as particularly shown in Figs. V and VI, the inner composite bifurcated 'section of the actuating lever includes the divergent arms 83 and 85 of substantially the same length and in vertical alignment when in operating position. The arms S3 and 36 are formed with forked end sections 89 and 90 adapted to straddle the shank of the handling member 60, as particularly shown in Fig. lV. The yielding acting arm or leaf spring is arranged with a predetermined preloading, so that its forked end 9) is in constant engagement with thel bottom surface of the enlarged head 70 of the handling member snugly straddling its shank and with the end of the forked section abruptly bent as at 91, so that the furcations are also in direct engagement with the side walls of the head 7@ of the handling member, thereby providing a constant pull on the diaphragm and: continuously guiding the handling member during its range of operation.

The rigid component of the actuating assembly, which has been identified as Si?, is preferably fabricated from sheet steel and is formed so that its back and side walls are substantially at right angles with the back having a substantially uniform width throughout its length. The side walls, as particularly shown in Fig. Vl, are struck out forming an enlarged section 92 adjacent to its pivotal axis and are provided with aligned apertures 93 to accommodate the pivot pin 8l and the remainder gradually decreasing in height froml the enlarged section 92 toward their respective extremities. The outer extremity of the arml 82 is provided with a contacting shoe 95 formed with a curved arcuate face 96 for engagement with the camV or continuously rotatingl part 7S.

The operation of the second form of the invention is similar in all` respects to the one hereinbefore described, as illustrated in Figs. I to lll inclusive. However, it should be noted that in the second' form of the invention, the curvature is imparted to the rigid arm instead of the leaf spring which,` as hereinbefore pointed out', is flat and forms a continuation of the uniplanar section of the lever proper.

The foregoing clearly shows that in the embodiments of the invention disclosed, the actuating assembly, which transmits motion and force from the continuously rotating part to the handling member of the diaphragm, acts as an elastic coupling which, not only transmits force and motion, but also functions in a four-fold manner as follows: (l) as means to take up any shock caused by the engagement of the lever means with the handling member of a pumping element, insuring thereby quiet operation by suppressing uncontrolled movements and undesirable vibrations, particularly in the critical speed range, (2) as means to effectively guide the handling member and thereby the pumping element during its operative range, (3) as means to provide a unidirectional force for keeping under tension the pumping element and applying a force in only one direction on the fulcruming means, and (4)l as means to constantly urge one component of the assembly into engagement with the continually power-driving part.

In the operation of pumps of the character to which this invention is directed, various inertia forces are encountered, both in starting' the diaphragm from rest or after back pressure in the pumping chamber has subsided. As the result of such conditions, the diaphragm must be started from rest and, with extreme rapidity, brought to a speed equal to that of its operating mechanism. These :inertia forces are considerable and frequently cause stress deterioration to the various components, espectially after continuous operation. In accordance with the present invention, such inertial forces are damped as the actuating lever provides a composite arm as a basic component of the continuous elastic connection between the operating cam and the diaphragm. By the presence of the cornposite arm in such elastic connection sufficient pressure is exerted on the lever for holding its outer arm into constant contact with the cam, without additional springs, while permitting, and in fact aiding, the handling member to undergo changes in position as result of pressure in the pumping chamber.

It has been found that by the variable line or length of contact provided between the lever proper and the leaf spring, the delivery efciency of the pump is greatly increased in the critical speed range and the pulsations caused by the iiuid transfer are damped orsuppressed, increasing thereby the diaphragm operating life as well as that of the seal for the handling member.

It is to be understood that the above detailed description of the present invention is intended to disclose an embodiment thereof to those skilled in the art, but that the invention is not to be construed as limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of `being practiced and carried out in various ways without departing from the spirit of the invention. The language used in thespecification relating to the operation and function of the elements of the invention is employed for purposes of description and not of limitation, and it is not intended to limit the scope 10 able handling member of light construction attached to said pumping element by one end and provided with an enlarged head at its other end, a composite actuating assembly operable by power means to impart motion in the opposite direction to said pumping element through said handling member distorting said resilient means, a rigid pivoted lever formed of sheet metal of channelshaped cross-section forming a part of said composite assembly having sections extending in opposite directions from its pivotal axis with its outer end section operatively connected to the power means for imparting movement to said handling member, a leaf spring having one end secured to said lever and formed at its other end with a forked section terminating in upwardly directed portions dimensioned to snugly straddle the shank and directly engage the side walls of the enlarged head of the handling member forming thereby the sole guiding means for said handling member during its range of movement, and the of the following claims beyond the `requirements of the Y `prior art.

What is claimed:

l. A pump having a housing providing a pumping chamber, a diaphragm comprised in the pumping chamber as the movable wall thereof, a hermetically sealed freely movable handling member of light construction operably connected to said diaphragm by one end and having an enlarged head at its other end, an operating composite lever pivotally mounted on the housing adapting the composite lever to be given` a rocking motion by a poweroperated means, said composite lever having an outer end projecting outside of said housing and an inner end inside of the housing, the major part of said composite lever formed by a rigid arm and a secondary inherently elastic arm connected together and having a diverging relationship from a point rearwardly of the pivotal axis of the composite lever to their terminal ends, both of the arms of said composite lever having forked end sections wbich straddle said handling member, the secondary arm having its forked section abruptly bent at its end and dimensioned to snugly straddle the shank of the handling member and directly engage the bottom and side walls of the enlarged head of said handling member toprovide thereby the sole guiding means therefor during its range of movement by placing said diaphragm'under constant pull and concurrently urging the outer end of the composite lever into constant engagement with the poweroperated means as well as constantly applied force in only one direction on the pivotal axis of said lever.

2. A pump comprising a reciprocable pumpingelement having resilient means for conditionally effecting its motion in one direction and a hermetically sealed freely movsaid leaf spring secured to the lever at a point rearwardly of its pivotal axis and having its main portion spaced apart from the lever from a point rearwardly of its pivotal axis tothe end of its inner section to thereby constantly apply a force in one direction on the pivotal axis of the level during its motion as well as providing a continuous pull on the pumping element by its direct engagement with the handling member.

3. For use in imparting motion providing a variable stroke from a continually driven part having a uniform throw to a reciprocable pumping element having a freely movable handling member of light construction attached thereto by one end and having an enlargement at its other end; a composite actuating assembly interposed between the continually driven part and the handling member which comprises a pivoted lever of sheet metal having a channel-shaped cross-section formed with an outer uniplanar surface` for actuation by said constantly driven part and a noise-obviating resilient means operated by the lever, the noise-obviating means including a yielding acting member extending in spaced relation from the lever from a point rearwardly of its pivotal point to its inner end forming divergent arms one of which is curved while the other arm is an extension of the uniplanar surface of the said sheet metal lever, both arms having forked end sections which straddle the shank of the handling member, the forked section of the yielding acting member abruptly bent at its end and dimensioned to snugly straddle the shank of the handling member and directly engage the bottom and side walls of the enlargement of the handling member forming thereby the only guiding means for the handling member during its range of movement providing a continuous pull on the pumping element by its direct engagement with the handling member.

References Cited in the 'nle of this patent UNITED STATES PATENTS 1,738,786 McKinley Dec. 10, 1929 1,742,746 Zubaty Jan. 7, 1930 1,957,669 Rockwell May 8, 1934 2,426,965 Coffey Sept. 2, 1947 2,653,544 Katcher Sept. 29, 1953 FOREIGN PATENTS 834,108 France Nov. 14, 1938 

